A simulation game is well known in which a view point is placed in a given position in virtual space and a virtual image seen from the view point is synthesized and displayed. In such a game, by placing an object in virtual space and displaying a virtual image of the object from the view point based on the distance between the view point and the object, on a direction from the view point, etc., reality is provided as if a user were in the virtual space. One of contrivances to enhance reality in a game is the use of sound effects for which various contrivances is provided. For example, a game device is disclosed in Patent Literature 1 in which sound being heard in a position of a virtual camera is reproduced by changing a mixing ratio of different two pieces of sound data according to the distance between a source of an effect sound and the virtual camera. According to this game device, by increasing a ratio of sound data for near distance for sound reproduction when the distance between the sound source and virtual camera is small, it is made possible to output an effect sound that can provide more reality.    Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. 2005-046270.